1. Facts and Myths of the LHC, and the consequences for Astronomy By: Stephen Demjanenko

2. Outline (Really) Quick History of Particle Physics LHC ▫Design ▫Detectors ▫Goals ▫Test Run Applications of Astrophysics

3. Quick History of Particle physics Began with the study of the atom and has now progressed to subatomic ▫Protons, neutrons, electrons, antimatter as well as constituents (quarks) As of the 1970’s particle theory was condensed into the Standard Model ▫Predicts 252 unique particles Since then work has been done to go beyond the Standard Model ▫The LHC hopes to test this as well as complete the Standard Model with the discovery of the Higgs

4. First Particle Accelerator John D. Cockcroft and Ernest Walton ▫Cavendish Laboratory In 1930 they managed to accelerate protons across a potential of 800 kilovolts 1932 – they split a lithium nucleus into alpha particles

5. Major Particle Accelerators Brookhaven National Laboratory – Relativist Heavy Ion Collider ▫Gold and other ions, polarized protons Fermilab – Tevatron (proton-antiproton) Stanford - SLAC (electron-positron) *CERN – LHC (proton-proton) Cornell Electron Storage Ring ▫Not major but its here at Cornell ▫40 ft below practice football/track fields

6. LHC Overview Built by the European Organization for Nuclear Research (CERN) 10,000 scientists collaborated Cost ~ $8 billion Generates 1 GBps of data

8. What it is not A weapon Earth’s Doomsday blackhole/wormhole creator

9. Myths Recently Walter L. Wagner and Luis Sancho sued CERN over the use of the LHC claiming it would destroy the planet ▫Did the same thing for FERMILAB The case was thrown out

10. Black Hole Myth The LHC does have the ability to create a black hole However, by Hawking radiation, all black holes are evaporating ▫Slow for large black holes but for any black hole the LHC could create it would evaporate in about 10 -17 s Once again, the LHC is SAFE

12. Cosmic Rays Cosmic rays are continually hitting the atmosphere  high energy extragalactic particles ▫Have energies similar/greater than the LHC can achieve  Nothing bad has happened yet  The Earth is still here LHCf experiment

13. So what is it? The LHC is the most powerful particle collider ever built ▫Took 14 years of planning/construction It will collide two proton beams at 14 TeV (7 TeV each beam) ▫Also can collider lead ions (2.74 TeV)

14. Where is it? Located 100m underground Is in Switzerland and France Located in the old LEP collider tunnel ▫Reused existing tunnel with a few modifications ▫3.7m in width, 27km in circumference

17. Design 1,232 dipole magnets, 392 quadrupole magnets ▫Maintains circular path and focuses the beam respectively ▫Weigh about 27 tons each ▫Twin bore design used to reduce space  Also magnetically couples the two beams 700,000 liters of liquid helium are used for cooling (1.9K) Base energy is 450 GeV and a couple times a day they are accelerated to 7 TeV

20. Beam Injection

22. Detectors Could see up to 600 million collisions per second 6 different detectors for different types of collisions ▫LHCf

24. ATLAS General purpose detector Higgs particle extra dimensions (could explain weakness of gravity)? Dark matter? 44m long, 25m in diameter Weighs 7,000 tons Most complex detector ever built

26. CMS Also a general purpose detector Works with ATLAS to detect the Higgs Also looks for dark matter (WIMPs) ▫Weakly interacting massive particles  Also known as cold dark matter

28. ALICE Studies quark-gluon plasma that existed shortly after the big bang LHC is 100,000 hotter than center of sun ▫Might be hot enough to free quarks from within protons Will observe how the plasma cools and creates subatomic matter

30. LHCb Will try to explain the asymmetry between matter and anti-matter ▫There is much more matter than antimatter Will study the bottom quark

32. TOTEM 440m long, 5m wide, 5m high 20 tons Will be located inside the CMS detector Size of proton Beam luminosity

34. Goals Understand the early universe better ▫Ion collider will be particularly useful for this Find experiments to test the validity of Grand Unified Theories, and possibly string theory Detect the predicted Higgs Boson ▫Expected to exist at energies this machine can reach

35. Standard Model Is the current accepted model of particle physics Explains the interactions between strong, weak and electromagnetic forces Does not include gravity Every predicted particle has been detected except for the Higgs Boson

36. Higgs Boson Principle of Inertia ▫A body in motion will continue in the same motion given there is no applied force Where does mass come from? Theory suggests that inertia comes from the interaction of a body with some resistive field

37. Higgs (cont.) The Higgs boson makes up this field LHC may produce a Higgs every hour ▫Would take 3 years to acquire enough data  Requires many events in order to statistically confirm its existence

38. Test Run The LHC started up on September 10 th at 4:27am sending a stream of protons around at 451 GeV There were no collisions – only one beam circulated On September 19 th the LHC was shutdown for repairs Is expected to resume operations in spring 2009

39. Problems with Test Run After 2 days of operation a transformer for the liquid helium failed and part of the tunnel warmed up ▫Wasn’t reported for a week ▫Took a week to cool that section back from 4.4 K to 2.1 K

40. Problems (cont.) A faulty electrical connection between two magnets caused a helium leak ▫Caused the collider to be taken offline for the remainder of the year 24 quadrupole and 8 dipole magnets were damaged

41. LHC@Home There is a distributed computing client which has been working about a year Works to simulate protons circulating in the LHC ▫Helps to develop a control sequence to maintain proton containment  Could cut into the magnets, taking the accelerator offline

42. Applications to Astronomy Clearly the LHC is not a telescope It does not make observations of the cosmos It does allow us to experiment with incredibly high energies, energies seen only in the first few seconds following the big bang Allows us to check validity of theories ▫We use these theories to model the evolution of the universe ▫Also helps us describe high energy astrophysics

43. Applications (cont.) As mentioned earlier the Higgs Boson is predicted to carry mass By better understanding gravity we can figure out why gravity is much weaker than any of the three other forces